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E-cigs strong risk for future smoking in teens

Non-smoking teens who vape on ‘one-way bridge’ to future smoking and less aware of harms

Louise Prime

Wednesday, 08 February 2017

Non-smoking teenagers who use e-cigarettes are on a ‘one-way bridge’ to becoming future smokers, and tend to lose the belief that smoking is harmful, US researchers have shown. They said the results of their small study*, published online today in Tobacco Control, provided a strong, scientifically-based rationale for restricting young people’s access to e-cigarettes.

The research team were concerned by the increasing prevalence of using e-cigarettes (vaping) among older schoolchildren in the US, and by growing evidence that vaping might be a ‘bridge’ to future use of conventional cigarettes. They designed a study to prospectively examine vaping as a predictor of future conventional cigarette smoking among young people with and without previous cigarette smoking experience, as well as to investigate whether or not vaping might desensitise them to the dangers of smoking.

To do this, they analysed prospective longitudinal panel data from the nationally representative Monitoring the Future study, which had surveyed 13,015 12th grade students from 122 schools in 2014. Their analysis was based on a randomly selected sample of 347 students out of those who completed in-school surveys in 2014 and again one year later.

The surveys included questions about substance use, including use of e-cigarettes and cigarette smoking. E-cigarettes were one of the most popular substances used; their use was about 50% more common than smoking.

The researchers reported that among students who had never smoked conventional cigarettes, vaping strongly predicted smoking initiation a year later. First use of a combustible cigarette at follow-up was reported by 31% of those who had recently vaped at the baseline survey, compared with 7% of students who had not. Even among non-smokers who at baseline reported the highest level of perceived risk for smoking, recent vaping was a strong predictor of smoking initiation – 33% for vapers compared with 7% among non-vapers. For those who had ever smoked by the time of the 2014 survey, the prevalence of smoking during the preceding 12 months was more than twice as high among teens who were also vapers in 2014 (80%) than it was among those who weren’t (37%).

Furthermore, among students who had smoked in the past but had not recently smoked at the time of survey, those who vaped were about twice as likely to have smoked at least one cigarette in the past 12 months at the follow-up – vaping had not diverted them from smoking.

Most of the respondents thought that cigarette smoking was harmful; 80% in both the 2014 and follow-up surveys said smoking one or more packs daily posed a ‘great risk.’ However, among teens who said they had never smoked by the time of the 2014 survey, recent vapers were four times as likely to move away from the belief that cigarette smoking poses a great risk as those who hadn’t vaped. The researchers suggested this could be cause they had become desensitised to the harms of smoking.

They pointed to several limitations in their study, such as not knowing what substances were in the e-cigarettes used, not allowing for student characteristics such as rebelliousness and the influence of friends, the relatively small number of responses to the follow-up survey, and the study’s observational nature – all of which mean no firm conclusions can be made about cause and effect.
Nevertheless, they concluded: "These results contribute to the growing body of evidence supporting vaping as a one-way bridge to cigarette smoking among youth. Vaping as a risk factor for future smoking is a strong, scientifically-based rationale for restricting youth access to e-cigarettes."

* Miech R, Patrick ME, O’Malley PM, Johnston LD. E-cigarette use as a predictor of cigarette smoking: results from a 1-year follow up of a national sample of 12th grade students. Tob Control 2017 Published online first doi 10.1136/tobaccocontrol-2016-053291.

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